Are you familiar with these notes?

> Alexander Kupers, "Zeeman's Conjecture," 2017.
[PDF download](http://people.math.harvard.edu/~kupers/notes/zeemansconjecture.pdf).

[![Fig4][1]][1]

Kupers refers to this as "a good reference":
> Sergei Matveev and Dale Rolfsen, 
"Zeeman’s collapsing conjecture," *Two-dimensional homotopy and
combinatorial group theory*, London Math. Soc. Lecture Note Ser., vol. 197, Cambridge Univ. Press,
Cambridge, 1993.


  [1]: https://i.sstatic.net/jdImG.png